Type D personality (the combination of negative affect and social inhibition) is associated with poor prognosis in cardiac patients. The current study aims to investigate the relationship between Type D and health-related behaviours. In a cross-sectional study, 200 healthy participants completed measures of Type D personality, and health-related behaviours. The results showed that Type D individuals engaged in more unhealthy behaviours including smoking, poor diet and lack of physical activity than non-Type D individuals. The association between Type D personality and maladaptive health behaviours may represent one mechanism to explain the link between Type D and ill-health.